Help with tutorial: "Blueprint Runtime Error: "Accessed None trying to read property "

Development Programming & Scripting
1

I am currently learning UE4, and following the “Making a Blueprint Product Configurator” tutorial, I am currently stuck on the “Material Swapping A, B and C” section. The goal is to make a couple of speakers, that when clicked, change materials. However, I keep getting this when I click the Speaker.:

  • Blueprint Runtime Error: “Accessed None trying to read property Speaker_Logic_Reference”. Blueprint: SpeakerBp Function: Execute Ubergraph Speaker Bp Graph: EventGraph Node: Cabinet Clicked *
    I have done it a couple more times, but still the same issue. I have no Idea what is going on and cannot complete the tutorial. Any help would be great.
2

With this error, the solution is always the same. Click the word on the far right in the error message, it will take you to the node that’s causing the problem. That node is being passed a reference which has not been assigned.